I ran my first 3k today.
It's the first time I have ever run/jogged that far in my life, 6 months ago I wouldn't even run up the stairs in the house without getting out of breath.
It took me aaaggessss (21 mintues) and I know it's nothing impressive compared to the runners on this part of the forum, but I got there and I'm aching really proud of it.
I guess what I am saying is that it CAN be done and you can do it. Just take it easy.